Food Safety Questions & Answers

Exposure to dioxins in the food supply stems largely from natural and man-made environmental sources. Dioxins break down very slowly in the environment and can be deposited on plants and taken up by animals. Dioxins may be concentrated in the food chain so that livestock, fish, and shellfish can have higher concentrations than the plants, water, soil, or sediments around them. The highest concentration of dioxins in livestock, fish, and shellfish, are typically found in fat and the liver.

Federal agencies have been aware of the presence of dioxins in foods since the 1970's and have been increasing their monitoring since the late 1990's, as technology to measure this group of compounds at very low levels has improved. The presence of dioxins in foods is not new, nor is it unique to the U.S. food supply. FDA and USDA have occasionally identified elevated levels that have led to actions to identify and reduce local dioxin sources. The contribution of dioxins to dietary exposure and the possible introduction via the use of particular feed components was identified by the National Academy of Sciences (NAS) Committee on the Implications of Dioxin in the Food Supply. The NAS report, issued on July 1, 2003, entitled "Dioxins and Dioxin-like Compounds in the Food Supply: Strategies to Decrease Exposure," was commissioned by the Dioxin IWG. We are continuing our efforts to reduce dioxin levels even further both in the environment and therefore in food and feed, and to identify food and feed production practices that can reduce dioxin levels in food and feed.

Yes. The U.S. food supply is among the safest and most nutritious in the world. Although the federal food and environmental agencies are concerned about dioxin, EPA's final Dioxin Reanalysis, Volume 1 (noncancer) document does not change the government's view of the overall safety of the food supply in this country. Maintaining the safety of the food supply is a top priority of the federal government.

Consumers should eat a balanced diet and follow the Dietary Guidelines for Americans, 2010, and should not avoid any particular foods because of dioxin. Each group provides important nutrients needed for health.

Meat, milk, and fish are important sources of nutrients for the American public and an appropriate part of a balanced diet. Milk is a major source of calcium, vitamins A and D, and riboflavin; meat is an important source of iron, zinc and several B-vitamins; fish provides beneficial fatty acids as well as certain vitamins and minerals. Each of these foods provides high quality protein in the diet. Lean meat includes meats that are naturally lower in fat, and meat where visible fat has been trimmed. For fish and poultry you can reduce fat by removing the skin. Reducing the amount of butter or lard used in the preparation of foods and cooking methods that reduce fat (such as oven broiling) may also lower the risk of exposure to dioxin. These strategies help lower the consumption of saturated fats as well as reduce the risk of exposure to dioxin.

Similarly, the 2003 NAS report titled "Dioxins and Dioxin-like Compounds in the Food Supply: Strategies to Decrease Exposure" identified options to be considered to reduce dioxin exposure through food-consumption pathways. One of these options was promoting changes in dietary consumption patterns of the general population that more closely conform to recommendations to reduce consumption of animal fats, such as the recommendations of the Dietary Guidelines for Americans, 2010. Another recommendation of the 2003 NAS report was to identify food production practices that can reduce dioxin levels in food.

You should also pay attention to local fishing advisories for fish that you catch yourself (see also F6). Fishing advisories may exist that provide recommended consumption rates of particular kinds of fish from particular water bodies where local contamination has occurred. If you do not know whether a water body that you fish in is covered under a fishing advisory, call your local or state health or environmental protection department and ask for their advice. (They are listed in the blue pages of your local telephone directory.) Ask them if there are advisories on the kinds or sizes of fish that should not be eaten from the water body. You can also ask about fishing advisories at local sporting goods or bait shops where fishing licenses are sold.

For most people, adjusting their diet to be consistent with recommendations found in the Dietary Guidelines for Americans, 2010 will result in multiple health benefits, including reduced dioxin exposure. The Dietary Guidelines for Americans, 2010 provide the best scientifically based advice on what constitutes a healthy diet and provide guidance on how to plan a varied diet choosing individual foods from a number of food groups. These groups include whole grain products such as breads and cereals, fruits and vegetables, seafood, lean meats, and fat-free or low-fat milk and milk products. However, some people consume more foods high in saturated fats (meat and dairy) than is recommended in the Dietary Guidelines for Americans, 2010. For these people, there are well-known and significant health benefits from reducing saturated fat consumption.. The Dietary Guidelines for Americans, 2010 however, do not recommend that people avoid all fats, as fats are an important part of balanced nutrition.

We need a certain amount of fat for a healthy, balanced diet. Fats supply energy and essential fatty acids, and they help the body absorb fat-soluble vitamins (A, D, E, and K). You need some fat in the food you eat. The Dietary Guidelines for Americans, 2010 recommend that fat intake be no more than 20 to 35% of your total energy intake, with less than 10% coming from saturated fats. For a person who consumes 2000 calories this means a total fat intake of less than 65 grams, including 20 grams or less of saturated fat. See the Nutrition Facts Label on food products for more information on fat content of food items. The Dietary Guidelines for Americans, 2010 do not recommend that you avoid all fats, but recommend an appropriate level of lean meats and low or fat-free dairy products and recommend reducing the use of spreads or cooking fat made from animal fat. This advice regarding saturated fats is consistent with a strategy to reduce dioxin exposure.

Good food safety practices like washing food and countertops will reduce risk of foodborne illness from microbial infection, but they cannot reduce dioxin levels. However, food preparation methods that reduce fat in the food you eat (such as trimming fat and broiling) may help to reduce dioxin exposure.

FDA and USDA's FSIS monitoring has been focused on food products in which there is a greater potential to contain dioxins. In the past, it was more difficult to detect or monitor the low levels of dioxins in foods. Recent improvements in dioxin testing methods have allowed the Federal government to expand its monitoring efforts. In addition, animal feed and feed components have emerged as important factors that may predict and contribute to the dioxin levels in certain foods derived from animals and, therefore have also been included in government monitoring efforts.

FSIS began to monitor dioxins in domestically produced beef, pork, and poultry products with a survey of each of these products being conducted between 1994 and 1996 (163 total samples). A larger survey of these products was conducted in 2002-2003 (510 total samples). FSIS completed another survey of 510 domestic beef, pork, and poultry samples for dioxins in 2008. Results from this survey and previous surveys in the mid 1990s and 2002-2003 can be found on the FSIS Web site at: http://origin-www.fsis.usda.gov/Fact_Sheets/Dioxin_Resources/index.asp.

Since 1995, FDA dioxin monitoring has involved several hundred samples a year, primarily commercial fish/shellfish and dairy products from grocery stores and distribution centers across the country. In 1999, FDA began annual monitoring for dioxins as part of FDA's Total Diet Study (TDS). TDS is a yearly market basket program that determines levels of various pesticide residues, industrial contaminants, and nutrients in foods collected in four geographic regions of the country.

In addition to the TDS samples, FDA conducts additional non-TDS (targeted) sampling of food and animal feed in an effort to gather additional information on dioxin. FDA collected approximately 550 food and feed samples in 2001 and approximately 1,050 food and feed samples in 2002 for dioxin analysis. FDA expanded the program to approximately 1,700 food and feed samples in 2003, 2004 and 2005, and collected and analyzed approximately 1,100 food and feed samples in 2006, 2007, 2008, 2009, 2010 and 2011. FDA plans to collect and analyze approximately 1,100 food and feed samples in 2012 and include additional analytes (nine dioxin-like PCB congeners) in select samples. FDA has posted data for dioxin levels in TDS and non-TDS samples and posted exposure estimates using these results. For more information about FDA's posted data for dioxin levels in TDS and non-TDS samples and exposure estimates see http://www.fda.gov/Food/FoodborneIllnessContaminants/ChemicalContaminants/ucm077444.htm. For more information about FDA's TDS see http://www.fda.gov/Food/FoodScienceResearch/TotalDietStudy/default.htm

6a. In addition to EPA’s RfD, have other safety/risk assessment levels for dioxin been established?

Yes. Other organizations have developed safety/risk assessment levels for dioxin. The Joint Expert Committee on Food Additives (JECFA) of the World Health Organization and the Food and Agriculture Organization of the United Nations has developed a Provisional Tolerable Monthly Intake (PTMI) of 70 pg/kg bw for dioxin (converted to 2.3 pg/kg bw-day). In addition, the U.S. Agency for Toxic Substances and Disease Registry/Center for Disease Control and Prevention (ATSDR) has established a chronic-duration oral Minimal Risk Level (MRL) of 1.0 pg/kg bw-day for 2,3,7,8-TCDD.

6b. Why are these safety/risk assessment levels different and am I at risk of health effects if I exceed them?

The safety/risk assessments have been conducted by different organizations and these organizations have relied on somewhat different data and include different scientific assumptions and safety/uncertainty factors. Despite these differences, the overall safety/risk assessment levels between JECFA, ATSDR and the EPA are fairly minor. Safety/uncertainty factors are used to account for uncertainty in the data used in the assessment and to also account for inter- and intraspecies variability and sensitivity. Since all these safety/risk assessment levels have safety/uncertainty factors built into them, there generally will be some margin of safety between them and estimates of exposure to dioxin. For those estimates of exposure that do exceed these levels, there is some reduction in the normal margin of safety. The margin of safety does not disappear and in all probability the potential chronic exposure does not represent an increase in risk. These safety/risk assessments also assume that exposure will be constant and for a lifetime, so exposures that exceed these assessment levels on a temporary or transitory basis represent little or no change in risk.

To date FDA and FSIS monitoring of food show that when detectable levels are found they are generally consistent with EPA estimates for background dietary occurrence of dioxins (see also G7). It is also important to note that known and quantifiable industrial emissions of dioxins in the United States have been reduced significantly since 1987. In addition, recent measurements show that dioxin levels in humans have also been reduced.

There have been multiple incidents involving dioxin in food in past years that received national and international attention. In these incidents, the dioxin levels were higher than background levels typically seen in foods tested by FDA or FSIS. In the first incident, in 1997, elevated levels of dioxins were found in some farm-raised fish and poultry products. The levels in fish, poultry, and eggs during this incident were about 10 times higher than background levels. FDA, FSIS, and EPA quickly launched an investigation. That investigation revealed that particular clay from one mine in Mississippi used as an additive to animal feed was responsible for the higher dioxin levels. The clay, which appears to have naturally occurring dioxins, was withdrawn from use as an animal feed ingredient. The government is continuing to monitor these foods and will address any situations identified.

In a second incident, in 1999, elevated levels of dioxins were discovered in some Belgian animal products, and the source of the dioxins was traced to animal feeds from a particular source. The U.S. government stopped the import of certain foods from a number of European countries until it could be either established that dioxin contaminated feeds were not fed to the slaughtered animals, or that food derived from the slaughtered animals did not contain elevated dioxins. The levels of dioxins in this incident were a hundred or more times higher than what the current background levels are in similar foods in the United States.

A more recent incident, in 2008, involved elevated levels of dioxin in pork products in Ireland. The source of the dioxin was traced to contaminated animal feed. The cause of the contaminated feed was thought to be through use of contaminated fuel oil used for drying the affected feed. In 2011, elevated levels of dioxin were also found in German farms that received animal feed containing oil that was produced using a contaminated fatty acid. Animal feed produced with the contaminated oil was delivered to pig, poultry, dairy cattle, bovine, rabbits and goose/duck farms in Germany.

Relevant federal agencies have taken a number of actions to reduce dioxin levels in food. EPA has taken aggressive actions to reduce dioxin emissions into the environmental by placing strict regulatory controls on all of the major industrial sources of dioxins. The known, quantifiable industrial emissions have been reduced by more than 75% from their levels in the 1980's as a result of EPA's efforts, along with efforts by state government and private industry.

In the long-term, efforts to reduce dioxin in the environment will also reduce dioxin levels in food and feed. FDA and FSIS have been monitoring the dioxin levels in food and feed and conducting investigations whenever a particular food has dioxin levels detected over the background levels in that food. If the investigation determines a specific source of the increased dioxins, FDA and FSIS take action to remove that source where practicable.

Yes. Studies consistently show that breastfed infants are healthier than formula fed infants. This statement is even more relevant now than in the past, when the levels of dioxin in breast milk were higher than they are today. There are overwhelming benefits of breastfeeding both for the mother and her infant. The American Academy of Pediatrics and many other professional organizations have concluded that the benefits of breastfeeding far outweigh the potential effects of environmental contaminants in breast milk. Breast milk is known to be the most complete form of nutrition for infants, with benefits for infant health, growth, immunity, and development. The benefits of breastfeeding for children include fewer cases and less severity of diarrhea, respiratory infections, and ear infections. Breastfeeding may also reduce the risk of sudden infant death syndrome and lower rates of childhood cancer.

In addition to the benefits for children, breastfeeding also has benefits for mothers. For example, several studies have found the risk of breast cancer to be higher for women who have never breastfed.